The present invention relates to a force-sensing device for measuring a force that acts in a predetermined direction on a location of force introduction of the force-sensing device, wherein the location of force introduction is rigidly connected by a yoke with at least one measuring spring that is elastically deformable by the force introduction, while the measuring spring(s) with the other end is/are arranged on the support that is designed to be rigidly connectable to the machine frame and wherein the force-caused deformation of the measuring spring(s) is detected at predetermined measuring locations and evaluated.
Such force-sensing device is disclosed in EP 0 621 469 B1. This force-sensing device has a special feature in that, for measuring a force expected to act in a predetermined direction, a pair of measuring springs are provided that are parallel to one another and spaced apart from one another. This arrangement is referred to as a “double bending beam”; however, in connection with the present invention this is not to be understood as a limitation to such arrangements of measuring springs. Therefore, for measuring such forces, all conceivable measuring spring arrangements are taken into consideration, i.e., also single bending beams, shearing force sensors, torsion sensors etc.
An important feature of this known force-sensing device—without being limited to it—is the arrangement of two parallel measuring springs that are connected with one end to a support that is to be connected rigidly to the machine frame. The other ends of the measuring springs are connected to one another by means of a yoke. By means of the yoke, the force to be measured is introduced into the system.
With this arrangement of support, measuring springs, and yoke, the yoke is displaced always parallel to itself when loaded. Such force-sensing devices have significant advantages with regard to stiffness and reproducible signal generation. In particular, they are able to detect high nominal loads even for minimal deflections.
Of course, this does not apply in the case of other possible measuring arrangements (single bending arrangement, shearing force sensor, torsion sensor etc.); however, they are suitable for the present invention as well.
When the yoke is moreover provided with a rolling bearing seat, it is possible to very well manufacture with such a force-sensing device also so-called measuring rollers that are characterized in particular in that also the rolling bearing is always displaced parallel to itself under load.
It is therefore an object of the present invention to configure the known force-sensing device in such a way that, while maintaining the aforementioned known advantages of measuring springs of different designs, a high stiffness can be achieved even for load directions that are outside of the predetermined direction in which the force to be measured acts.